PGT-A Testing: Should You Screen Your Embryos Before Transfer?

What Is PGT-A — And Why Are More Patients Asking About It?

If you've started your IVF journey, you may have come across the term PGT-A — Preimplantation Genetic Testing for Aneuploidies. It sounds complex, but the concept is straightforward: before an embryo is transferred into your uterus, a small number of cells are biopsied and tested to check whether the embryo has the correct number of chromosomes.

Chromosomally normal embryos are called euploid. Those with an abnormal chromosome count are called aneuploid — and aneuploid embryos are one of the leading reasons IVF cycles fail, or pregnancies end in early miscarriage. PGT-A is designed to identify the best embryo before transfer, rather than after a failed attempt reveals a problem.

At Iswarya Fertility, we are increasingly having detailed conversations with patients about whether PGT-A belongs in their treatment plan — because it isn't a one-size-fits-all recommendation, and you deserve to understand both the benefits and the limitations before making this decision.

How PGT-A Actually Works

The process integrates seamlessly into a standard IVF cycle, but with a few important additions:

1. Egg retrieval and fertilisation proceed as normal during your stimulated cycle.
2. Embryos are grown in the laboratory until they reach the blastocyst stage, typically on Day 5 or Day 6 of development. At this stage, the embryo has two distinct cell populations: the inner cell mass (which becomes the baby) and the trophectoderm (which becomes the placenta).
3. An embryologist performs a trophectoderm biopsy — carefully removing 5 to 8 cells from the outer layer. This does not harm the embryo's developmental potential.
4. The biopsied cells are sent to a specialist genetics laboratory, where Next Generation Sequencing (NGS) analyses all 23 pairs of chromosomes for abnormalities.
5. Your embryos are vitrified (frozen) while results are awaited — usually within 7 to 14 days.
6. Only chromosomally normal embryos are selected for a frozen embryo transfer in a subsequent cycle.

The result is a ranked, scientifically prioritised list of embryos — giving your medical team the clearest possible picture of which embryo to transfer first.

Who Is Most Likely to Benefit From PGT-A?

The honest answer is that PGT-A offers the greatest benefit to specific patient groups. Research consistently shows measurable improvements in outcomes for:

• Women over 35 — The rate of chromosomal abnormalities in embryos rises significantly with age. By 40, studies suggest that more than half of all blastocysts may be aneuploid. PGT-A helps identify the viable embryos within a cohort, reducing the number of unsuccessful transfers.
• Patients with recurrent miscarriage — If you have experienced two or more pregnancy losses, chromosomal abnormalities in embryos are frequently a contributing factor. Screening allows you to transfer only embryos that have passed chromosomal assessment.
• Couples with recurrent implantation failure — When good-quality embryos repeatedly fail to implant despite a receptive uterus, aneuploidy is often implicated. PGT-A can help break this cycle.
• Patients with a previous chromosomally abnormal pregnancy — Including a prior Down syndrome, Edwards syndrome, or Patau syndrome diagnosis.
• Those with a limited number of embryos who want to prioritise the highest-potential embryo for their first transfer.

The Limitations You Should Also Know About

PGT-A is a powerful tool, but it is important to approach it with realistic expectations. Here are the key considerations your doctor should discuss with you:

It does not guarantee a successful pregnancy

Transferring a euploid embryo significantly improves the probability of success, but chromosomal normality is only one factor in implantation. Uterine receptivity, endometrial lining quality, and immune factors all play a role.

Mosaicism creates grey areas

Some embryos are found to be mosaic — meaning they contain a mixture of normal and abnormal cells. These embryos occupy a clinical grey area. Research shows that some mosaic embryos can self-correct and result in healthy pregnancies, but decisions about transferring them require careful, individualised discussion.

It may reduce your usable embryo number

If you have a small cohort of embryos, PGT-A may reveal that most are aneuploid — which can be emotionally difficult to process. In younger patients with good ovarian reserve, this is rarely a concern, but it is worth discussing your specific situation with your fertility specialist before proceeding.

It adds cost and time

PGT-A is an additional investment. For some patients, particularly younger women under 35 with no history of miscarriage, the evidence for routine PGT-A is less compelling — and the cost may not be justified without a specific clinical indication.

PGT-A Versus PGT-M: Understanding the Difference

Patients sometimes confuse PGT-A with PGT-M (Preimplantation Genetic Testing for Monogenic disorders). While PGT-A screens for numerical chromosome abnormalities across all chromosomes, PGT-M tests for a specific known genetic condition carried by one or both parents — such as cystic fibrosis, sickle cell disease, or thalassaemia. Both tests use embryo biopsy, but they answer very different questions. If you or your partner carries a known hereditary condition, PGT-M is the relevant test — and the team at Iswarya Fertility can guide you through both options depending on your family history and medical background.

Making the Decision: Questions to Ask Your Doctor

If you are considering PGT-A, here are the most useful questions to bring to your consultation:

• Based on my age, history, and embryo numbers — do you recommend PGT-A for my specific situation?
• What is the expected aneuploidy rate for someone my age?
• How does your laboratory handle mosaic embryos?
• Will PGT-A change the treatment plan, or is it confirmatory?
• What happens if all my embryos come back aneuploid?

These are not easy questions — but they are the right ones. Fertility treatment works best when decisions are made collaboratively, with full information on both sides.

Your Next Step

PGT-A is one of the most meaningful advances in modern IVF — but its true value lies in being used thoughtfully, for the right patients, at the right time. If you are navigating a complex fertility journey and wondering whether genetic embryo testing could improve your outcomes, Iswarya Fertility offers specialist consultations where we review your complete history and help you make a decision that is truly right for you — not just statistically average.

Reach out to us today to speak with one of our fertility specialists. Clearer answers, better decisions, and a more confident path forward starts with the right conversation.

Frequently Asked Questions

Does PGT-A testing harm the embryo?

The biopsy used for PGT-A removes cells from the trophectoderm — the outer layer that becomes the placenta — not from the cells that develop into the baby. When performed by an experienced embryologist, the procedure does not harm the embryo's developmental potential, and vitrification immediately after biopsy preserves the embryo safely.

At what age should I consider PGT-A for my IVF cycle?

PGT-A is most strongly recommended for women aged 35 and above, as chromosomal abnormality rates in embryos rise significantly with age. However, it may also be recommended at any age if you have a history of recurrent miscarriage, recurrent implantation failure, or a previously chromosomally abnormal pregnancy.

What happens if all my embryos are aneuploid after PGT-A?

If all embryos are found to be aneuploid, your fertility specialist will discuss your options — which may include a further stimulation cycle to create more embryos, reviewing mosaic embryo transfer in certain circumstances, or exploring donor egg IVF. While this outcome is emotionally difficult, knowing before transfer prevents repeated failed cycles.

How accurate is PGT-A testing?

PGT-A using Next Generation Sequencing (NGS) is considered highly accurate for detecting numerical chromosomal abnormalities, with reported accuracy rates above 97% for full aneuploidies. However, it cannot detect all genetic conditions — it screens for chromosome number, not specific gene mutations, which is why PGT-M is a separate test.

Does transferring a PGT-A normal embryo guarantee pregnancy?

No — chromosomal normality significantly improves implantation and live birth rates, but it is not the only factor involved. Endometrial receptivity, uterine anatomy, and other biological variables also influence whether an embryo successfully implants. PGT-A improves your odds; it does not remove all uncertainty.